Switch Actuator Research Articles

Research on an Off-Chip Microvalve for Pneumatic Control in Microfluidic Chips

A compact, rapid, and portable off-chip pneumatic control valve is significant for the miniaturization and integration of external pneumatic systems for microfluidic chips. In this work, an off-chip microvalve with a high-speed electromagnetic switch actuator and a polydimethylsiloxane (PDMS) material valve body has been designed to be easily encapsulated, simulated using MATLAB/Simulink software, and tested in a micromixer. Multi-physical coupling mathematical models are developed based on the elastic deformation force of the valve membrane, the driving force of the valve core, and the fluid force in the microchannel. Two single microvalves are used to form a three-way microvalve, which can control the air pressure in a pneumatic microchannel on the microfluidic chip. The relationship between the flow–duty cycle, the flow–pressure difference of the single electromagnetic microvalve, and the load pressure of the three-way microvalve is simulated and analyzed. Sample mixing performance controlled by the proposed off-chip three-way microvalve was tested to evaluate the pneumatic control capability, and the results show that the undertaking can fully satisfy the needs of a pneumatic microfluidic chip for most applications.

Naphthalimide‐Based Aggregation‐Induced Emissive Polymeric Hydrogels for Fluorescent Pattern Switch and Biomimetic Actuators

Front Cover: In article 2000123, Wei Lu, Tao Chen and co-workers prepare a robust aggregation-induced emissive polymeric hydrogel by copolymerization of N-isopropylacrylamide and a specially designed 4-phenoxy-N-allyl-1,8-naphthalimide (PhAN) monomer. The hydrogel is characterized with thermally controlled emission/transmittance response, and its potential applications as a fluorescence pattern switch and biomimetic actuator are demonstrated.

Naphthalimide-Based Aggregation-Induced Emissive Polymeric Hydrogels for Fluorescent Pattern Switch and Biomimetic Actuators.

Substituted naphthalimide (NI) moieties are highly versatile and newly recognized aggregation-induced emission (AIE) building blocks for many potentially useful smart molecules, polymers, and nanoparticles. However, the introduction of NI fluorophore into cross-linked polymeric networks to prepare AIE-active hydrogels still remains underdeveloped. Herein, a novel naphthalimide-based aggregation-induced emissive polymeric hydrogel is reported, followed by its proof-of-concept applications as fluorescence pattern switch and biomimetic actuator. The hydrogel, bearing semi-interpenetrating polymer networks, is synthesized starting from N-isopropylacrylamide, hydroxyethyl methacrylate, and a newly designed NI monomer (4-phenoxy-N-allyl-1,8-naphthalimide, PhAN). Rational molecular design for AIE-active PhAN monomer lies in modification of the NI core with rigid and bulky phenoxy group to break its planarity to produce desirable propeller-shaped molecular conformation. The as-prepared hydrogel is proved to be a aggregation-induced blue-light-emitting hydrogel. It also shows volume phase transition behavior and is endowed with thermally responsive synergistic emission and transmittance change, thus enabling simultaneous regulation of two optical properties merely by one single stimulus. These useful advantages further encourage fabrication of several proto-type fluorescence pattern switching and biomimetic actuating devices. This study may not only enlarge the list of fluorescent hydrogels but also serve as a novel smart optical platform for potential anticounterfeiting, sensing, displaying, or actuating applications.

Assessment of Mechanical Crack Fault Dependent on Wavelet Finite Element Model

Given that cracks in the forging and heat treatment process of switch actuator rod can affect its service life, damage mechanics is combined with the finite element analysis method to calculate the fatigue crack propagation life by using the Paris equation. The wavelet finite element model is used to establish the GM (1,1) grey differential equation. The identification parameter of the model is determined by experimental data calculation to assess the fatigue crack life of the switch actuator rod and compare it with the measured data in the experiment. The results show that the application of the wavelet finite element model to assess the fault of switch actuator rod is simple, feasible, and highly accurate, with excellent application value.

Comparative Analysis of Two Actuators for High Voltage Bypass Switch

The bypass switch is required to complete the closing operation quickly and accurately protect the transmission line. Therefore, there is a high requirement for the actuator of the bypass switch. According to the characteristics of the bypass switch, the commonly used actuators are compared, and the magnetic force actuator and the motor actuator are initially selected to meet the requirements. Firstly, the characteristics of the magnetic and motor actuator are compared and analyzed in principle. Then, the optimization model of the two actuators is obtained through simulation optimization. Under the same working voltage, the action characteristics of the two actuators, including the action speed, the start time and the output force, are compared. Finally, a comprehensive reference for the selection of the bypass switch actuator is provided.

Model-Based Controller Design for a Lift-and-Drop Railway Track Switch Actuator

Track switches are essential in order to enable railway vehicles to change routes; however, they are also the largest single cause of failure on the railway network. A new generation of switching concepts are emerging from projects like In2Rail, REPOINT, and S-Code that promise to improve rail network performance through the use of new mechanisms, monitoring, and control systems. This paper focusses on modeling and control of a lab-demonstrator from the REPOINT project. Unlike conventional track switch machines, this actuator needs closed loop feedback control. First, a detailed simulation model of the actuator is developed and validated against experimental results. Two model-based control designs are then developed and tested: a classical cascaded P/PI controller and a modern state feedback controller. The two controllers are compared and it is found that, whilst there are some performance differences, both meet the requirements for use in a redundantly actuated REPOINT switch.

Fast high-fidelity information transmission through spin-chain quantum wires

Spin chains have been proposed as quantum wires for information transfer in solid-state quantum architectures. We show that huge gains in both transfer speed and fidelity are possible using a minimalist control approach that relies only on a single local on-off switch actuator. Effective switching time sequences can be determined using optimization techniques for both ideal and disordered chains. Simulations suggest that effective optimization is possible even in the absence of knowledge of the Hamiltonian or accurate models.

Global controllability with a single local actuator

We show that we can achieve global density-operator controllability for most $N$-dimensional bilinear Hamiltonian control systems with general fixed couplings using a single, locally acting actuator that modulates one energy-level transition. Controllability depends upon the position of the actuator and relies on the absence of either decompositions into noninteracting subgroups or symmetries restricting the dynamics to a subgroup of $\mathrm{SU}(N)$. These results are applied to spin-chain systems and used to explicitly construct control sequences for a single binary-valued switch actuator.

Acoustical switch for a directional microphone

An acoustical switch is provided for a directional microphone of a hearing aid device. The hearing aid device includes a faceplate having a switch aperture, a front port, and a rear port. The microphone includes a front inlet in communication with the front port within the face plate and a front chamber of the microphone. The microphone further includes two rear inlets in communication with the rear port within the faceplate and a rear chamber of the microphone. The acoustical switch comprises a switch actuator having a body portion and a lever portion. The body portion includes a first closure surface and a second closure surface. The switch actuator is adapted to be disposed within the switch aperture of the face plate of the hearing aid device such that the body portion is disposed adjacent to the inlets of the microphone. The switch actuator s moveable between a first position wherein the first closure surface of the body portion is adapted to cover one of the rear inlets of the microphone, and a second position wherein the second closure surface of the body portion is adapted to cover the other of the rear inlets of the microphone. The body portion includes a side surface having an acoustical resistance associated therewith wherein the acoustical resistance is substantially greater than an acoustical resistance between either of the ports and its respective microphone chamber.

Mems optical switches with guaranteed switching status

Techniques for controlling and monitoring MEMS optical switches are disclosed. In one embodiment, an electronic feedback loop is employed to determine a control signal to a MEMS switch actuator in accordance with an instruction. The control signal is so determined in such a way that the switching statuses are maximally guaranteed. To generate an appropriate control signal, AC or DC impedances of the MEMS switch are detected and used to configure the control signal to drive the switch. When it is detected that the impedance changes do not meet respective thresholds, the control signal is adjusted. In the case that the stiction happens, the switch actuator is overcharged, discharged and repeatedly applied for a limited time to overcome the stiction.

A human-factors evaluation of switch actuators for use in spacecraft

The characteristics of switch actuators for communications equipment to be used in spacecraft are investigated. Subjects operated common switch actuators with space-suit gloves, under both atmospheric pressure and two-psi pressure differential. The independent variables studied were type of actuator, direction of operation, actuating torque, number of switch positions, effect of pressure, practice effect, and position on the panel. The dependent variables (criteria) were operating time, errors, and ranks. Switch actuators, in general, were operated more slowly and with more errors under simulated spacecraft conditions than under ordinary conditions. It was found that multiposition switches must have firm detent or interlocking features to prevent overshoot or accidental reversal. The best switch actuator under all circumstances combined is shown in Fig. 1.